A coated fine particle comprisisng: (i) a complex of a drug and a cationic lipid, wherein (a) the drug is a nucleic acid and the complex is obtained by mixing the drug and the cationic lipid in water, wherein the complex has a diameter of 10 nm to 1,000 nm, and (ii) a lipid layer formed of lipid(s), wherein the lipid(s) is selected from phospholipid, glyceroglycolipid, sphingoglycolipid, cholesterol and synthetic lipid, wherein the complex is coated with the lipid layer.